At present, pipefitters use a regular carpenter's square with linear measurements for assisting them in measuring conventional pipes and elbows for cutting, fitting and the like. After taking measurements with a conventional carpenter's square with linear measurements, the pipefitter must utilize trigonometric tables, drafting board layouts, and complex calculations in order to properly setup the pipes and elbows for cutting, fitting, and the like.
According to the present invention, a square is provided -- of essentially the same overall size as a carpenter's square-for assisting a pipefitter in measuring pipes for cutting and fitting that eliminates the need for trigonometric tables, drafting board work, and the complicated calculations that are inherent in present procedures. The square according to the present invention has numeral indicia thereon corresponding to actual conventional pipe sizes rather than the abstract (for the purposes of pipifitting) linear measurement quantity provided on present squares. When utilizing the square according to the present invention, a pipefitter can directly readoff on the square the pipe size he is dealing with, no extraneous linear measurements being provided. According to another aspect of the present invention, numerical degree indicia are disposed along one edge of the square and are associated with an "apex" point on an opposed inside edge of the square, to allow one to accurately draw and solve angles. By utilizing the square according to the present invention, a pipefitter can accurately draw and solve angles, find actual take-offs or center radii of long 90.degree. elbows, find ordinates for saddle ons, find ordinates of mitered pipe, quarter the outside circumference of pipe, find the outside center of pipe, and mark an elbow to cut it on its proper axis -- as well as many other related functions -- without the need to resort to trigonometric tables, drafting board work, and complicated calculations.
The square according to the present invention -- as is true for conventional squares -- comprises a tongue and a body extending perpendicular to the tongue, the tongue and body each having inside and outside edges intersecting each other at inside and outside heels respectively, and each having a face surface and a back surface. Distinct from the squares of the prior art, according to the present invention a plurality of markings are disposed on at least one edge of the square, each of the markings having numeral indicia associated therewith corresponding to an actual conventional pipe size. According to the present invention, pipes having the following conventional sizes may readily be worked with: 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 24, and 30. Markings disposed along one of the square edges may comprise markings that are spaced a distance from a reference equal to the actual outside radius for the conventional numeral indicated pipe, the reference comprising a reference line indicated "outside center" and/or the square inside heel. This allows the square to be used as a center finder and for quartering pipe. Other markings may be disposed along an edge that are spaced a distance l.5 PS from a given reference, wherein PS is the pipe size numeral indicia corresponding with the marking, the reference comprising the outside heel and/or a reference line, and allowing the pipe to be used for finding the actual take-off or center radius of a long 90.degree. elbow. Another edge may have markings that are spaced therealong from a reference corresponding to the formula IRP .times. .beta. wherein IRP is the actual inside radius for a conventional particular pipe corresponding to the numeral indicia, and wherein .beta. is the angle formed by division of a circumference into a number of divisions q so that .beta. = 360.degree./q, such markings being used for finding ordinates for saddle ons. Additionally, one or more edges may have markings that are spaced therealong from a reference corresponding to the formula ORP .times. .beta. wherein ORP is the actual outside radius for a conventional particular pipe corresponding to the numeral indicia, such markings being used for finding ordinates for mitered pipe, and for finding ordinates for saddle ons. Another set of markings may be provided along one edge, a particular numeral indicia having three sets of markings corresponding thereto, for marking an elbow for cutting on its proper axis.
According to another aspect of the present invention, for drawing and solving angles, one of the square tongue face edges has markings with numerical degree indicia associated therewith, each of the markings comprising a line disposed at a numerically indicated angle .alpha. with respect to an edge of the body face, all the lines intersecting the body face edge at a common APEX point, each of the lines being located the distance DP from a square heel wherein DP = DA .times. tan .alpha., DA being the distance the common APEX point is spaced along the body edge from the same square heel from which the distance DP is measured.
It is the primary object of the present invention to provide a square for use with pipefitting that allows a pipefitter to cut and fit conventional pipe and elbows without resort to trigonometric calculations, drafting board work, complex calculations, and the like. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.